Liquid-liquid junction membranes prepared from a modified polyvinylchloride (PVC) polymer with 0.6 weight percent (w/o) OH introduced, (PVC-OH) and 0.25 w/o SIC14 added during casting have substantially enhanced adhesion on glass or Si compared to PVC-based membranes. Ion-selective electrodes for NH4 + based on a dioctyladipate/nonactin ion exchanger show enhanced adhesion, as do Ca 2 § membranes using a neutral ion carrier/o-nitrophenyloctylether mixture. Enhanced surface adhesion is demonstrated to result in improved lifetime for K § membranes coated on n-Si electrodes and on ion-sensitive field effect transistors (ISFET's). Electron micrographs show large differences in surface quality for PVC vs. PVC-OH/SiC14-based membranes after aqueous storage.Integrated potentiometric sensors such as the ion-sensitive field effect transistor (ISFET) utilize ion-selective electrode (ISE) technology to produce membrane-coated devices specific to a variety of ions (1). However, the typical polyvinylchloride (PVC) liquid-liquid junction-based membranes used with an ISE are not ideally suited to application to solid-state devices. Problems with membrane lifetime due to leaching of material from the membrane (2) and poor adhesion (3)to the sensor arise. Recently, we reported on a K+-sensitive ISE membrane, based on a chemically modified form of PVC, that exhibits enhanced adhesion on solid surfaces with minimal changes in electrochemical properties (4). Formation of a covalent bond between PVC and a solid surface is accomplished via synthesis of the hydroxyl-substituted derivative, PVC-OH (0.6 weight percent [w/o] OH) and reaction with SIC14 according to Scheme I. In this paper we demonstrate that the ~c,-I ~8i-.o. -o-/-o-..l ~ o,

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